The evolving classification of dementia: placing the DSM-V in a meaningful historical and cultural context and pondering the future of "Alzheimer's"

Identifying dementia using medical data linkage in a longitudinal cohort study: Lothian Birth Cohort 1936

BACKGROUND

The Lothian Birth Cohort 1936 (LBC1936) is a longitudinal study of ageing with well-characterised assessments, but until now, it has relied on self-report or proxies for dementia such as cognitive tests. Our aims were twofold: a) to describe a framework for identifying dementia in a cohort study. b) to report the age-specific incidence and prevalence of all-cause dementia and dementia subtypes in 865 individuals in the LBC1936.

METHODS

Electronic Health Records (EHR) of all participants were reviewed, and relevant information was extracted to form case vignettes for everyone with any record of cognitive dysfunction. The EHR data sources include hospital and clinic letters, general practitioner and hospital referrals, prescribed medications, imaging and laboratory results. Death certificate data were obtained separately. Clinician assessments were performed when there was concern about a participant's cognition. A diagnosis of probable dementia, possible dementia, or no dementia was agreed upon by a consensus diagnostic review board, comprised of a multidisciplinary team of clinical dementia experts who reviewed case vignettes and clinician assessment letters. For those with probable dementia, a subtype was also determined, where possible. We compared the agreement between our newly ascertained dementia diagnoses with the existing self-reported dementia diagnoses.

RESULTS

Self-reported dementia diagnoses were positive in only 17.8% of ascertained dementia diagnoses. The EHR review identified 163/865 (18.8%) individuals as having cognitive dysfunction. At the consensus diagnostic review board, 118/163 were diagnosed with probable all-cause dementia, a prevalence of 13.6%. Age-specific dementia prevalence increased with age from 0.8% (65-74.9 years) to 9.93% (85-89.9 years). Prevalence rates for women were higher in nearly all age groups. The most common subtype was dementia due to Alzheimer disease (49.2%), followed by mixed Alzheimer and cerebrovascular disease (17.0%), dementia of unknown or unspecified cause (16.1%), and dementia due to vascular disease (8.5%).

CONCLUSIONS

We present a robust systematic framework and guide for other cohort teams wanting to ascertain dementia diagnoses. The newly ascertained dementia diagnosis provides vital data for further analyses of LBC1936 to allow exploration of lifecourse predictors of dementia.

Ethical issues in early diagnosis and prevention of Alzheimer disease

This paper considers ethical issues related to early diagnosis and all forms of prevention of Alzheimer disease and related conditions. It offers a critical view of the current state of scientific, clinical, and social responses to the growing number of older people with cognitive challenges, and suggests how priorities going forward should be different from those receiving most attention today. We begin with a review of global policy efforts, consider the fundamental goals of prevention, examine issues surrounding early diagnosis, explore more deeply values associated with efforts to prevent age associated cognitive decline, and conclude by considering often unexplored ethical issues that contextualize the field and should influence our approaches to the future.

Revisiting the intersection of amyloid, pathologically modified tau and iron in Alzheimer's disease from a ferroptosis perspective

The complexity of Alzheimer's disease (AD) complicates the search for effective treatments. While the key roles of pathologically modified proteins has occupied a central role in hypotheses of the pathophysiology, less attention has been paid to the potential role for transition metals overload, subsequent oxidative stress, and tissue injury. The association of transition metals, the major focus heretofore iron and amyloid, the same can now be said for the likely pathogenic microtubular associated tau (MAPT). This review discusses the interplay between iron, pathologically modified tau and oxidative stress, and connects many related discoveries. Basic principles of the transition to pathological MAPT are discussed. Iron, its homeostatic mechanisms, the recently described phenomenon of ferroptosis and purported, although still controversial roles in AD are reviewed as well as considerations to overcome existing hurdles of iron-targeted therapeutic avenues that have been attempted in AD. We summarize the involvement of multiple pathological pathways at different disease stages of disease progression that supports the potential for a combinatorial treatment strategy targeting multiple factors.

Learning From the Cultural Challenge of Dementia

Learning from the profound challenge of dementia is an urgent priority. Success will require a critical deconstruction of current cultural and linguistic representations of this condition, and a kindling of novel and courageous approaches to re-conceptualise dementia's meaning and experience. This symposium collects provocative ideas arising from various discourses, theoretical perspectives, and methodolgical approaches to explore new ways to understand dementia.

Somaticization, the making and unmaking of minded persons and the fabrication of dementia

This article examines the strategies by which the different and variable signs of failing mental powers become known sufficiently for 'dementia' to be made into a stable bio-clinical entity, that can be tested, diagnosed and perhaps one day even treated. Drawing on data from ethnographic observations in memory clinics, together with interviews with associated scientists and clinicians, we document the challenges that clinicians face across the clinical and research domain in making dementia a stable object of their investigation. We illustrate how the pressure for early diagnoses of dementia creates tensions between the scientific representations of early dementia and its diagnosis in the clinic. Our aim is to highlight the extent to which the work of diagnosing dementia involves an intricate process of smoothing out seemingly insurmountable problems, such as the notoriously elusive connections between brain/mind and body/person. Furthermore, we show that a part of this process involves enrolling patients as minded, agentic subjects, the very subjects who are excluded from dementia science research in pursuit of biomarkers for the pre-clinical detection of dementia.

Cultural representations of dementia

In a Perspective, Alexandra Hillman and Joanna Latimer discuss cultural representations of dementia in the media, film, and literature.

Little White Lies: Interrogating the (Un)acceptability of Deception in the Context of Dementia

This metasynthesis surveyed extant literature on deception in the context of dementia and, based on specific inclusion criteria, included 14 articles from 12 research studies. By doing so, the authors accomplished three goals: (a) provided a systematic examination of the literature-to-date on deception in the context of dementia, (b) elucidated the assumptions that have guided this line of inquiry and articulated the way those shape the research findings, and (c) determined directions for future research. In particular, synthesizing across studies allowed the authors to develop a dynamic model comprised of three temporally linear elements-(a) motives, (b) modes, and (c) outcomes that describe how deception emerges communicatively through interaction in the context of dementia.

The New Conceptualization of Alzheimer's Disease under the Microscope of Influential Definitions of Disease

BACKGROUND

According to its new conceptualization, Alzheimer's disease (AD) has preclinical and symptomatic phases, and biomarker abnormality justifies the diagnosis of the disease.

METHODS

The conceptual validity of AD is assessed on the basis of the disease definitions of T. Szasz, R.E. Kendell and J.G. Scadding, C. Boorse, K.W.M. Fulford and J.C. Wakefield, as well as of the DSM-5 classification system.

RESULTS

The new AD conceptualization could fit the Szaszian disease definition, provided that AD biomarkers reflected the pathological hallmarks of a singular disease, but it seems that they do not. Moreover, preclinical AD does not yield a biological disadvantage, being a central criterion for justifying the presence of a disease according to the disease definition of Scadding and Kendell. In addition, it remains unclear whether abnormality of biomarkers in elderly people embodies a statistical deviation from normal ageing and a pathological characteristic. Furthermore, not all stages of AD are related to experiences of failure of intentional doing, which is the criterion of the disease definition of Fulford, whilst the Wakefieldian harmful dysfunction and the DSM-5 mental disorder criteria are fulfilled only in the symptomatic phases of the disease course.

DISCUSSION

Our analytical endeavours unveiled weak sides and the fuzzy boundaries of the new conceptualization of AD. Future refinements of the criteria should address them so that the validity of the AD concept is increased.

Time to reinvent the science of dementia: the need for care and social integration

OBJECTIVES

The increasing number of older adults with dementia is a large and growing public health problem. Alzheimer's disease, the prevailing form of dementia, is projected to quadruple worldwide. To date, the care and social integration of individuals with dementia is complicated by limited collaborations between biomedicine and other disciplines. The objective of this paper is therefore to reflect on the orientation of biomedicine with regard to the science of dementia, and to articulate a path for moving forward.

METHODS

The authors drew upon, and expanded, the insights of an interdisciplinary, international workshop entitled 'Bioethics and the Science of Aging: The Case of Dementia' held in October 2012 at the University of California in Berkeley.

RESULTS

The care of individuals with dementia compels solid interdisciplinary collaborations. There are several issues affecting the care of individuals with dementia: (1) an evolving definition of dementia; (2) the ambiguous benefits of the diagnosis of dementia; (3) ethical conflicts concerning consent processes and clinical trials; and (4) a limited understanding of the perspective of the person with dementia.

CONCLUSION

We argue that it is time for a renewed dialogue between biomedicine and other disciplines -- particularly public health, the social sciences, the medical humanities and bioethics. This interdisciplinary dialogue would facilitate a process of self-reflection within biomedicine. This dialogue will also provide the foundation for equitable public health interventions and will further prioritize the values and preferences of individuals with dementia, as well as their care and social integration.

Public health guidance to facilitate timely diagnosis of dementia: ALzheimer's COoperative Valuation in Europe recommendations

OBJECTIVE

ALzheimer's COoperative Valuation in Europe (ALCOVE) was a Joint Action co-financed by the European Commission to produce a set of evidence-based recommendations for policymakers on dementia. This paper reports on timely diagnosis.

METHODS

Evidence was reviewed from scientific, policy and qualitative research. An online questionnaire was completed by experts from 24 European Union countries detailing current practice. An iterative process with people with dementia, family carers and professionals was utilised to develop recommendations.

RESULTS

Advances in the technical aspects of diagnosis have changed what is understood by early diagnosis. Although research into preclinical stages is crucial, diagnosing at these very earliest stages is not recommended as regular practice. On balance, it is suggested that citizens should have access to accurate diagnosis at a time in the disease process when it can be of most benefit to them. The term timely diagnosis is used to reflect this. The diagnosis can help citizens and their families make sense of what is happening and make lifestyle changes and plans for the future. The central principles identified to maximise benefit and to reduce harm associated with diagnosis at an earlier stage included reducing stigma about dementia; respecting the rights of the individual; recognising that how the diagnosis is given will impact on subsequent adjustment and that post diagnostic support are required for the person and their family. Detailed recommendations are provided for timely detection, the diagnostic process, complex diagnoses, response to early cognitive changes and workforce.

CONCLUSIONS

The recommendations can be utilised at a local, national and European level to benchmark progress.

The end of Alzheimer's disease--from biochemical pharmacology to ecopsychosociology: a personal perspective

The future of the Alzheimer's disease (AD) field involves a more complete understanding not only the state of current scientific approaches, but also the linguistic and cultural context of preclinical and clinical research and policy activities. The challenges surrounding dementia are large and growing but are only part of broader social and health concerns. In this latter context, the current state of research in the AD area is reviewed together with necessary priorities in moving forward. Creating a more optimistic future will depend less on genetic and reductionist approaches and more on environmental and intergenerative approaches that will aid in recalibrating the study of AD from an almost exclusive focus on biochemical, molecular and genetic aspects to better encompass "real world" ecological and psychosocial models of health.

A two-decade comparison of prevalence of dementia in individuals aged 65 years and older from three geographical areas of England: results of the Cognitive Function and Ageing Study I and II

BACKGROUND

The prevalence of dementia is of interest worldwide. Contemporary estimates are needed to plan for future care provision, but much evidence is decades old. We aimed to investigate whether the prevalence of dementia had changed in the past two decades by repeating the same approach and diagnostic methods as used in the Medical Research Council Cognitive Function and Ageing Study (MRC CFAS) in three of the original study areas in England.

METHODS

Between 1989 and 1994, MRC CFAS investigators did baseline interviews in populations aged 65 years and older in six geographically defined areas in England and Wales. A two stage process, with screening followed by diagnostic assessment, was used to obtain data for algorithmic diagnoses (geriatric mental state-automated geriatric examination for computer assisted taxonomy), which were then used to estimate dementia prevalence. Data from three of these areas--Cambridgeshire, Newcastle, and Nottingham--were selected for CFAS I. Between 2008 and 2011, new fieldwork was done in the same three areas for the CFAS II study. For both CFAS I and II, each area needed to include 2500 individuals aged 65 years and older to provide power for geographical and generational comparison. Sampling was stratified according to age group (65-74 years vs ≥75 years). CFAS II used identical sampling, approach, and diagnostic methods to CFAS I, except that screening and assessement were combined into one stage. Prevalence estimates were calculated using inverse probability weighting methods to adjust for sampling design and non-response. Full likelihood Bayesian models were used to investigate informative non-response.

FINDINGS

7635 people aged 65 years or older were interviewed in CFAS I (9602 approached, 80% response) in Cambridgeshire, Newcastle, and Nottingham, with 1457 being diagnostically assessed. In the same geographical areas, the CFAS II investigators interviewed 7796 individuals (14,242 approached, 242 with limited frailty information, 56% response). Using CFAS I age and sex specific estimates of prevalence in individuals aged 65 years or older, standardised to the 2011 population, 8·3% (884,000) of this population would be expected to have dementia in 2011. However, CFAS II shows that the prevalence is lower (6·5%; 670,000), a decrease of 1·8% (odds ratio for CFAS II vs CFAS I 0·7, 95% CI 0·6-0·9, p=0·003). Sensitivity analyses suggest that these estimates are robust to the change in response.

INTERPRETATION

This study provides further evidence that a cohort effect exists in dementia prevalence. Later-born populations have a lower risk of prevalent dementia than those born earlier in the past century.

FUNDING

UK Medical Research Council.

Epidemiology of dementias and Alzheimer's disease

BACKGROUND AND AIMS

Global population aging has been one of the defining processes of the twentieth century, with profound economic, political and social consequences. It is driving the current epidemic of dementia, both in terms of its extent and global distribution. The aim of the study was to summarize recent findings relevant to the epidemiological knowledge of dementia and Alzheimer's disease (AD).

METHODS

A narrative mini-review of the literature relevant to the epidemiology of dementia and AD is presented, summarizing important findings and analyzing their implications.

RESULTS

It was estimated that in 2010 there were 36.5 million people living with dementia, with 7.7 million new cases yearly and a new case of dementia every 4 sec. The number of persons living with dementia will nearly double every 20 years. Most of these persons will be living in low- and middle-income countries (LMIC).

CONCLUSIONS

There are a substantial number of people with dementia worldwide and these numbers will continue to increase mainly in LMIC, producing a wide range of impacts. It is important to make dementia a national public health and social care priority worldwide. Recent reviews and meta-analyses have failed to clearly identify a singular causal or preventive pathway for AD that seems to be a multicausal, heterogeneous and age-related condition.

Neurocognitive diagnostic challenges and the DSM-5: perspectives from the front lines of clinical practice

The proposed changes to the DSM-IV-TR are an attempt to advance a common language to be used by clinicians and researchers in psychiatry in the United States. Any improvement brought about by these changes may be jeopardized unless the ICD-10, which is used by non-psychiatric clinicians and researchers worldwide, and the DSM resolve the differences in the definitions and diagnostic criteria of most disorders. Unless there is congruence between the two manuals, debate is therefore likely to continue in the literature as to which provider is best suited to direct the care for the person with dementia: primary care providers, psychiatric providers, or neurologists. The changes to the DSM-IV-TR have the potential to promote preventive measures and early diagnosis, provided that the stigma associated with mental illnesses can be mitigated. A common language among psychiatric and primary care APRNs, other clinicians, and researchers will enhance effective communication and improve dementia care.